Not Applicable
1. Field of the Invention
This invention is in the field of personal flotation devices used to preserve the lives of persons going overboard from a watercraft, or going overboard during the sinking of a watercraft.
2. Background Art
Lives are unnecessarily lost at sea every year because of the inability of would-be rescuers to locate in a timely fashion an overboard person in distress. As three days is the generally-accepted physical limit for a human body to do without potable water, time is of the essence not only in locating, but also in actually rescuing, a person adrift in open waters. In busy waterways, time is even more of the essence, as the potential for inadvertent rundown is ever-present.
In some situations, a boat can suddenly and inexplicably sink without warning. The boaters may have just enough time to don life vests before being plunged into the water. Even when other boats are in the area, and even if those boats are looking for the people in the water, weather and sea conditions can make the victims"" exact locations difficult to determine, and prevent a timely rescue.
Currently, search teams may be aided in rescue missions of a person missing at sea by the distressed individual""s use of mirrors, flashlights, flares, whistles, and dye markers. These are sometimes ineffective, with the result that the distressed person drowns.
Military personnel are sometimes equipped with a radio-beacon homing device, but this is generally simply providing a homing target, and not transmitting location data. The typical homing device follows the inverse square law of physics, as the signal decreases in amplitude in proportion to the distance from the beacon to the would-be rescuer. As a result, if a signal for rescue were to be transmitted from a great distance, a substantially large power transmission system is required, as well as a high antenna, for the transmission to be effective.
Some boaters utilize a sea rescue system consisting of a water-activated strobe and a howling signal aboard the boat, to alert crew members on the boat of a xe2x80x9cman overboard,xe2x80x9d as well as an automatic boat engine shutdown and a Global Positioning System (GPS) location marker. This type of system may not be helpful when the boat sinks, or when there are no able-bodied personnel remaining on the boat.
A system disclosed in U.S. Pat. No. 5,650,770 to Schlager, et al., xe2x80x9cSelf-Locating Remote Monitoring Systems,xe2x80x9d discloses an embodiment incorporating a GPS system, but this system requires an xe2x80x9celectronic handshakexe2x80x9d and repetitive polling between a base station on the boat and each remote unit (i.e., the life vest of the person overboard). In other words, distress signals from a source, such as the survivors of a boat which has sunk 20 miles off the coast, would not be picked up by an unrelated rescue station on land. In fact, no communication with a land station is disclosed. Additionally, the Schlager et al. system does not signal distress until the remote unit, representing the victim in distress, has traveled beyond a predetermined distance from the base station, thus triggering the base station to instruct the remote unit to initiate distress signaling from the victim to the base station (typically, the boat in a man-overboard situation). Continuous polling of the remote unit by the base station repetitively measures the distance between the base station and the remote unit, to determine whether an alarm condition exists, and to instruct the remote unit to initiate distress signaling. The electronic handshake prevents false alarm signaling, but it requires an extra piece of equipment to render the system operable, and it makes the system dependent upon a minimum separation distance between the remote unit and the base station. In summary, the electronic handshake in the Schlager system may work very well between a boat and the life vest worn by a man overboard, but, if the boat has sunk, the system breaks down and a long-distance open-sea rescue mission will not be summoned.
The Schlager et al. system not only has the absolute necessity for an electronic handshake, but also a limitation on distress signaling only when the victim is farther away from the base station than a predetermined distance. The Schlager system, therefore, can not be adapted to provide distress signaling and position notification from a remote unit directly to an unrelated rescue station at some distance, such as a Coast Guard station.
It would be desirable to have a self-contained sea rescue signaling unit utilizing a GPS receiver incorporated into an automated and xe2x80x9cfail-safexe2x80x9d personal flotation life-preserver rescue system, capable of sensing a true man-overboard situation on its own, and capable of sending a distress signal and reliable position data to an unrelated rescue station, even at a great distance.
In the present invention, a personal flotation device (PFD) is provided with a hydrostatic pressure sensor, a Global Positioning System (GPS) receiver, a satellite radio-telephone, and a controller. When the hydrostatic pressure sensor is submerged to a sufficient depth for a sufficient duration to indicate a true man-overboard situation, the controller energizes the GPS receiver to accurately determine the position coordinates of the device. Further, the controller energizes the satellite radio-telephone to transmit a distress signal and accurate position coordinates to a remote rescue station, such as a Coast Guard facility, via a satellite telephone system. The controller periodically de-energizes the satellite radio-telephone to conserve battery power, periodically powering up to repetitively transmit the distress and position signals. Further, if the hydrostatic pressure sensor indicates that the device has been removed from the water, the controller ceases transmission. An input device can also be incorporated, such as a keyboard or microphone, to allow the victim to control operation of the device or to transmit voice or data signals.
The present invention has no restrictions on where, or at what distance, distress signaling begins. Whether the distress signaling emanates from a victim adrift at sea one mile from land, or 1,000 miles from land; or whether or not the victim is within a predetermined distance from a boat; are of no importance in triggering distress signaling and location-pinpointing signaling. With the present invention, anytime whatsoever that a victim is adrift in water, regardless of the distance from a boat or other receiver, the sea-rescue life vest, after meeting fail-safe requirements as delineated below, automatically begins distress signaling and position-location signaling. Additionally, the present invention has no need for a base station, and no requirement for an xe2x80x9celectronic handshakexe2x80x9d to be in place.
The present invention provides:
1. a fool-proof means for automated distress signaling and location pinpointing for people adrift and in need of rescue anywhere in open waters; and,
2. a fail-safe system which prevents false alarms.
The present invention provides both of these functions with a relatively low power requirement, and a cumbersome antenna is not required, as the effect of a very high antenna is achieved by transmitting the distress and position signals via orbiting satellites.
The novel features of this invention, as well as the invention itself, will be best understood from the attached drawings, taken along with the following description, in which similar reference characters refer to similar parts, and in which: